US3858142A - Fuse and method of making same - Google Patents

Fuse and method of making same Download PDF

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Publication number
US3858142A
US3858142A US00371728A US37172873A US3858142A US 3858142 A US3858142 A US 3858142A US 00371728 A US00371728 A US 00371728A US 37172873 A US37172873 A US 37172873A US 3858142 A US3858142 A US 3858142A
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US
United States
Prior art keywords
activator
fusible
wire
fuse
fusible element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00371728A
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English (en)
Inventor
G Deelman
J Kramer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Olvis NV
Original Assignee
Olvis NV
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Filing date
Publication date
Application filed by Olvis NV filed Critical Olvis NV
Application granted granted Critical
Publication of US3858142A publication Critical patent/US3858142A/en
Assigned to BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIATION, reassignment BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIATION, SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TRACOR HOLDINGS, INC., TRACOR, INC., AND OTHERS INDICATED ON SCHEDULE SA
Assigned to TRACOR, INC. reassignment TRACOR, INC. RELEASED BY SECURED PARTY (SEE DOCUMENT FOR DETAILS). Assignors: BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIATION
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H69/00—Apparatus or processes for the manufacture of emergency protective devices
    • H01H69/02—Manufacture of fuses
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
    • H01H85/02—Details
    • H01H85/04—Fuses, i.e. expendable parts of the protective device, e.g. cartridges
    • H01H85/05—Component parts thereof
    • H01H85/055—Fusible members
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49107—Fuse making

Definitions

  • ABSTRACT Darby & Cushman
  • the present invention relates to a fuse comprising a fusible element mounted in a housing between two end terminals, the fusible element having the shape of a thin wire or strip and including activator means.
  • Such a fuse is known, for example, from an article in Bulletin des für für für für Praez. 53 (1962), pp. 585-592, and is generally considered particularly suitable for use as a retarded fuse.
  • the activator means may consist of a single activator core provided in the middle of the fusible element.
  • Activator cores on the basis of metals having low melting points, such as tin, lead and indium, are frequently used in retarded miniature fuses.
  • the activator core has the shape of a relatively thick blob of, for example, a tin-lead alloy secured by melting in the middle of the fusible wire, or the activator core consists of an eye filled with activator material in the middle of the fusible wire, which wire has been bent previously for this purpose.
  • the activator core is difficult to reproducibly provide such alloy cores, which renders it difficult to reproducibly manufacture retarded fuses for low current intensities.
  • the fusible element with the single activator core must be mounted highly accurately in the housing of the fuse, as in incorrect position has a detrimental effect on the limiting current of the fuse. Due to these difficulties and due to the poor control of the pre-diffusion of the activator material into the fusible wire or strip, the lower limit of the nominal current intensity for such fuses will be about 1.5 amp., while for lower current values one must resort to more complex structures employing extension springs, as disclosed on page 589 of the above article.
  • British Pat. No. 473,335 discloses fuses wherein an activator core containing magnesium powder is provided on the fusible wire. At a given current through the fusible element the magnesium in the core ignites and the interruption is established.
  • the magnesium-containing core may be provided, for example, by applying a paste including the material to the fusible wire.
  • a paste including the material to the fusible wire.
  • the application of paste to very thin wires is a difficult operation, while also the dosage and accurate positioning entails many problems.
  • an amount of oxygen is required for the burning of the magnesium, which causes difficulties in the case of fuses having very small dimensions.
  • the high ignition temperature of about 500 C causes a high degree of sagging of the fusible wire due to expansion, which entails the danger that the activator core located in the middle of the wire is inactivated as it contacts the wall of the housing. This danger is also present in the earlier mentioned fuses having an activator core on the basis of low melting point metals.
  • the activator means consist of a plurality of small activator cores closely spaced apart on the fusible wire or strip such that the axial position of the fusible element does not or hardly affect the limiting current of the fuse.
  • retarded fuses comprising fusible elements including activator cores for hitherto unattainably low nominal current values can be achieved with high accuracy.
  • the fuses according to the present invention may serve a retarded fuse wherein very small activator cores having a weight of some tens of micrograms or more are uniformly and closely spaced apart on a thin fusible wire having a thickness of 20 ,uum.
  • the present invention may also be applied to advantage to fuses wherein the fusible wire is wound about a core of insulating fibres.
  • the fusible wire in such a structure the fusible wire carries uniformly spaced small alloy cores.
  • the present invention also relates to methods of making the fuses according to the present invention.
  • small discs are punched from a strip of thinly rolled activator material whether or not applied to a thin flim substrate, the discs are disposed on the fusible wire of strip in the desired spaced apart relationship with the activator side facing the wire or strip, the wire being previously provided with an adhesive coating, the wire or strip with the discs is passed along a heating means so as to melt each disc to form an activator core on the fusible wire of strip, whereafter a desired length of the fusible wire or strip carrying the activator cores is mounted in an appropriate housing.
  • the discs are preferably punched with a substantially larger diameter than the diameter of the fusible wire or strip and the discs are melted by absorption of infrared radiation, the fusible wire or strip remaining at relatively low temperature.
  • a very thinly rolled strip of tin as activator material may be applied to a thin film substrate of a low melting point synthetic material, such as polythene. It is also possible to use a film of synthetic material whereon an extremely thin layer of tin or lead is deposited by evaporation. Discs having a diameter of about 1 mm are punched from such a strip. The discs can be prefolded and disposed on the fusible wire by means of a vacuum forceps.
  • the discs By passing the fusible wire carrying the discs along an infrared irradiator, the discs will absorb heat due to their relatively large surface areas that is just sufficient to melt the activator mass, the surface tension of this melted mass ensuring that a blob is formed around the relatively cool fusible wire.
  • very small activator cores are provided on a fusible element by applying a photoresist layer to the fusible element, locally exposing and etching the photoresist layer, selectively applying activator material to the fusible element by electroplating, and finally mounting the fusible element carrying the activator cores in an appropriate housing.
  • This method may be considered an analogy of etching processes for manufacturing printed circuitry panels. The local exposure is performed by selective intermittent use of a very fine light beam.
  • FIG. 1 represents a fuse according to the present invention
  • FlG. 2 represents a similar fuse showing the most unfavourable location of the activator cores that may occur when the fuse is assembled
  • FIG. 3 represents a different embodiment of the fuse according to the present invention.
  • the fuse comprises a housing consisting of a tubular section 1, which may be of glass or quartz, having end caps 4 of, for example, a conductive metal.
  • the fusible wire 2 carrying a plurality of uniformly spaced apart activator cores 3 of, for example, an alloy of tin and lead is stretched in the housing.
  • the sealing material 5 provides a sealing of the interior of the housing relative to the environment.
  • the length of the tube 1 may be e.g.
  • . 20 mm and the diameter may be e.g. 4.5 mm.
  • a long fusible wire is provided with uniformly spaced apart activator cores.
  • This wire is subsequently cut into sections having the desired length, which sections are mounted in housings.
  • the activator cores at the ends of the wire are in contact with the wall of the housing 1.
  • the contact between maximally two activator cores and the tube wall does not appear to affect the height of the limiting current of the fuse.
  • a fusible wire of s silver alloy having a thickness of about 60 um carries tin-lead cores of about pg spaced apart distances of 5 mm
  • a retarded miniature fuse is obtained having a nominal current of only 3l5 mamp.
  • FIG. 3 shows an embodiment of the fuse according to the present invention wherein the fusible element consists of a core 6 of insulating fibre material wound with an extremely thin silver wire 2.
  • the silver wire 2 carries closely spaced activator cores 3.
  • a fuse of this type comprisinga wound copper wire having a thickness of 15 um carrying alloy cores of each about 60 g povides a nominal current of mamp.
  • the fuse shown in FIG. 3 can be conveniently mechanically manufactured.
  • a method of making a fuse wherein small discs are punched from a strip of thinly rolled activator material, the discs then being disposed on a fusible wire in spaced apart relationship with the activator side facing the wire, the wire being previously provided with an adhesive coating, the wire with the discs being passed along a heating means so as to melt each disc to form an activator core on the fusible wire, whereafter a desired length of the fusible wire carrying the activator cores is mounted in an appropriate housing.
  • a method of making a fuse according to claim 1 wherein very small activator cores are provided on a fusible element by applying a photoresist layer to the fusible element, locally exposing and etching the photoresist layer and selectively applying activator material to the fusible element. by electroplating.
  • a fuse comprising a fusible element mounted in a housing between two end terminals, the fusible element having the shape of a thin wire and including activator means, the activator means consisting of a plurality of small activator cores spaced apart on the fusible wire such that the axial position of the fusible element does not appreciably affect the limiting current of the fuse, wherein the fusible wire of the fusible element is wound about a core of insulating fibres.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Fuses (AREA)
US00371728A 1972-06-22 1973-06-20 Fuse and method of making same Expired - Lifetime US3858142A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL727208554A NL151209B (nl) 1972-06-22 1972-06-22 Smeltveiligheid en werkwijze voor het vervaardigen van een dergelijke smeltveiligheid.

Publications (1)

Publication Number Publication Date
US3858142A true US3858142A (en) 1974-12-31

Family

ID=19816329

Family Applications (1)

Application Number Title Priority Date Filing Date
US00371728A Expired - Lifetime US3858142A (en) 1972-06-22 1973-06-20 Fuse and method of making same

Country Status (12)

Country Link
US (1) US3858142A (ja)
JP (2) JPS4951552A (ja)
AT (1) AT324473B (ja)
BE (1) BE801151A (ja)
CA (1) CA991687A (ja)
CH (1) CH560967A5 (ja)
DD (1) DD106923A5 (ja)
FR (1) FR2189855B1 (ja)
GB (1) GB1408365A (ja)
IT (1) IT992526B (ja)
NL (1) NL151209B (ja)
SE (1) SE394765B (ja)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4122426A (en) * 1976-02-03 1978-10-24 San-O Industrial Corp. Time-lag fuse
US4189696A (en) * 1975-05-22 1980-02-19 Kenneth E. Beswick Limited Electric fuse-links and method of making them
US4517544A (en) * 1983-10-24 1985-05-14 Mcgraw-Edison Company Time delay electric fuse
US5130689A (en) * 1989-05-09 1992-07-14 Leach & Garner Co. Intermetallic time-temperature integration fuse
US6618273B2 (en) 2001-03-27 2003-09-09 Wilson Greatbatch Ltd. Trace fuse
US6617953B2 (en) 2001-03-26 2003-09-09 Wilson Greatbatch Ltd. Link fuse
US20040104801A1 (en) * 2001-03-02 2004-06-03 Andre Jollenbeck Fuse component
US20120299692A1 (en) * 2007-10-09 2012-11-29 Littelfuse, Inc. Fuse providing overcurrent and thermal protection
CN102810433A (zh) * 2011-06-02 2012-12-05 兴亚株式会社 筒形电流保险丝的制造方法
US20150294829A1 (en) * 2012-11-17 2015-10-15 Pacific Engineering Corporation Fuse with a thermomechanical compensation element

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1545205A (en) * 1975-05-22 1979-05-02 Beswick Ltd K Electric fuse-links
AT353882B (de) * 1978-02-03 1979-12-10 Wickmann Werke Ag Schmelzsicherung

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1473284A (en) * 1921-05-17 1923-11-06 Frederick A Feldkamp Electric-fuse element
GB777125A (en) * 1954-06-04 1957-06-19 British Insulated Callenders A fuse arrangement primarily for use in electric capacitor installations

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB344892A (en) * 1929-12-13 1931-03-13 Charles Walter Cox Improvements in fusible elements for electric fuses
DE653383C (de) * 1930-06-12 1937-11-22 Siemens Schuckertwerke Akt Ges UEberlastungstraege, feuersichere Schmelzsicherungspatrone
GB473335A (en) * 1936-04-07 1937-10-07 Belling & Lee Ltd Improvements in and relating to fusible electric cutouts
US2815414A (en) * 1953-10-12 1957-12-03 Siemens Ag Electric fuse elements for retarded or rapid response
GB1086324A (en) * 1963-07-19 1967-10-11 English Electric Co Ltd Improvements relating to electric fuse elements
FR1442164A (fr) * 1964-08-06 1966-06-10 Siemens Ag Procédé de fabrication des conducteurs fusibles en forme de bande dans des éléments inertes de remplacement et conducteurs fusibles obtenus au moyen de ce procédé
NL142815B (nl) * 1970-09-15 1974-07-15 Olvis Smeltzekeringen Werkwijze voor het vervaardigen van een smeltveiligheid, in het bijzonder voor geringe stroomsterkte, alsmede aldus vervaardigde smeltveiligheid.

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1473284A (en) * 1921-05-17 1923-11-06 Frederick A Feldkamp Electric-fuse element
GB777125A (en) * 1954-06-04 1957-06-19 British Insulated Callenders A fuse arrangement primarily for use in electric capacitor installations

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4189696A (en) * 1975-05-22 1980-02-19 Kenneth E. Beswick Limited Electric fuse-links and method of making them
US4122426A (en) * 1976-02-03 1978-10-24 San-O Industrial Corp. Time-lag fuse
US4517544A (en) * 1983-10-24 1985-05-14 Mcgraw-Edison Company Time delay electric fuse
US5130689A (en) * 1989-05-09 1992-07-14 Leach & Garner Co. Intermetallic time-temperature integration fuse
US20040104801A1 (en) * 2001-03-02 2004-06-03 Andre Jollenbeck Fuse component
US7320171B2 (en) * 2001-03-02 2008-01-22 Wickmann-Werke Gmbh Fuse component
US20080084267A1 (en) * 2001-03-02 2008-04-10 Wickmann-Werke Gmbh Fuse component
US6617953B2 (en) 2001-03-26 2003-09-09 Wilson Greatbatch Ltd. Link fuse
US6618273B2 (en) 2001-03-27 2003-09-09 Wilson Greatbatch Ltd. Trace fuse
US20120299692A1 (en) * 2007-10-09 2012-11-29 Littelfuse, Inc. Fuse providing overcurrent and thermal protection
US9443688B2 (en) * 2007-10-09 2016-09-13 Littelfuse, Inc. Fuse providing overcurrent and thermal protection
CN102810433A (zh) * 2011-06-02 2012-12-05 兴亚株式会社 筒形电流保险丝的制造方法
CN102810433B (zh) * 2011-06-02 2016-08-24 兴亚株式会社 筒形电流保险丝的制造方法
US20150294829A1 (en) * 2012-11-17 2015-10-15 Pacific Engineering Corporation Fuse with a thermomechanical compensation element
US10431411B2 (en) * 2012-11-17 2019-10-01 Pacific Engineering Corporation Fuse with a thermomechanical compensation element

Also Published As

Publication number Publication date
JPS55157836A (en) 1980-12-08
NL7208554A (ja) 1973-12-27
IT992526B (it) 1975-09-30
DE2330894B2 (de) 1977-05-05
FR2189855A1 (ja) 1974-01-25
AT324473B (de) 1975-09-10
DD106923A5 (ja) 1974-07-05
NL151209B (nl) 1976-10-15
CH560967A5 (ja) 1975-04-15
FR2189855B1 (ja) 1976-09-17
CA991687A (en) 1976-06-22
JPS4951552A (ja) 1974-05-18
GB1408365A (en) 1975-10-01
DE2330894A1 (de) 1974-01-31
BE801151A (nl) 1973-12-19
SE394765B (sv) 1977-07-04

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AS Assignment

Owner name: BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIA

Free format text: SECURITY INTEREST;ASSIGNOR:TRACOR HOLDINGS, INC., TRACOR, INC., AND OTHERS INDICATED ON SCHEDULE SA;REEL/FRAME:005317/0726

Effective date: 19891030

AS Assignment

Owner name: TRACOR, INC.

Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIATION;REEL/FRAME:005953/0942

Effective date: 19911227